A new superlattice system suitable for infrared detection in the 8–12 &mgr;m wavelength range is proposed. The system is a sawtooth doping superlattice (SDS) constructed by alternatingn‐ andp‐type &dgr;‐doped layers in the narrow gap III‐V alloy InAs1−xSbx(x≊0.6). The electronic structure of such materials is examined theoretically using a multiband envelope function formalism. The results indicate that, with relatively modest doping levels (<4×1012cm−2) and short periods (<300 A˚), an InAs0.4Sb0.6SDS exhibiting significant optical absorption out to 12 &mgr;m at 77 K should be possible.